data_page_generator.rb

# coding: utf-8
# Generate pages from individual records in yml files
# (c) 2014-2016 Adolfo Villafiorita
# Distributed under the conditions of the MIT License

module Jekyll

    module Sanitizer
      # strip characters and whitespace to create valid filenames, also lowercase
      def sanitize_filename(name)
        if(name.is_a? Integer)
          return name.to_s
        end
        return name.tr(
    "ÀÁÂÃÄÅàáâãäåĀāĂ㥹ÇçĆćĈĉĊċČčÐðĎďĐđÈÉÊËèéêëĒēĔĕĖėĘęĚěĜĝĞğĠġĢģĤĥĦħÌÍÎÏìíîïĨĩĪīĬĭĮįİıĴĵĶķĸĹĺĻļĽľĿŀŁłÑñŃńŅņŇňʼnŊŋÑñÒÓÔÕÖØòóôõöøŌōŎŏŐőŔŕŖŗŘřŚśŜŝŞşŠšſŢţŤťŦŧÙÚÛÜùúûüŨũŪūŬŭŮůŰűŲųŴŵÝýÿŶŷŸŹźŻżŽž",
    "AAAAAAaaaaaaAaAaAaCcCcCcCcCcDdDdDdEEEEeeeeEeEeEeEeEeGgGgGgGgHhHhIIIIiiiiIiIiIiIiIiJjKkkLlLlLlLlLlNnNnNnNnnNnNnOOOOOOooooooOoOoOoRrRrRrSsSsSsSssTtTtTtUUUUuuuuUuUuUuUuUuUuWwYyyYyYZzZzZz"
  ).downcase.strip.gsub(' ', '-').gsub(/[^\w.-]/, '')
      end
    end
  
    # this class is used to tell Jekyll to generate a page
    class DataPage < Jekyll::Page
      include Sanitizer
  
      # - site and base are copied from other plugins: to be honest, I am not sure what they do
      #
      # - `index_files` specifies if we want to generate named folders (true) or not (false)
      # - `dir` is the default output directory
      # - `data` is the data defined in `_data.yml` of the record for which we are generating a page
      # - `name` is the key in `data` which determines the output filename
      # - `template` is the name of the template for generating the page
      # - `extension` is the extension for the generated file
      def initialize(site, base, index_files, dir, data, name, template, extension)
        @site = site
        @base = base
  
        # @dir is the directory where we want to output the page
        # @name is the name of the page to generate
        #
        # the value of these variables changes according to whether we
        # want to generate named folders or not
        if data[name] == nil
          puts "error (datapage_gen). empty value for field '#{name}' in record #{data}"
        else
          filename = sanitize_filename(data[name]).to_s
  
          @dir = dir + (index_files ? "/" + filename + "/" : "")
          @name = (index_files ? "index" : filename) + "." + extension.to_s
  
          self.process(@name)
          self.read_yaml(File.join(base, '_layouts'), template + ".html")
          self.data['title'] = data[name]
          # add all the information defined in _data for the current record to the
          # current page (so that we can access it with liquid tags)
          self.data.merge!(data)
        end
      end
    end
  
    class DataPagesGenerator < Jekyll::Generator
      safe true
  
      # generate loops over _config.yml/page_gen invoking the DataPage
      # constructor for each record for which we want to generate a page
  
      def generate(site)
        # page_gen_dirs determines whether we want to generate index pages
        # (name/index.html) or standard files (name.html). This information
        # is passed to the DataPage constructor, which sets the @dir variable
        # as required by this directive
        index_files = site.config['page_gen-dirs'] == true
  
        # data contains the specification of the data for which we want to generate
        # the pages (look at the README file for its specification)
        data = site.config['page_gen']
        if data
          data.each do |data_spec|
            index_files_for_this_data = data_spec['index_files'] != nil ? data_spec['index_files'] : index_files
            template = data_spec['template'] || data_spec['data']
            name = data_spec['name']
            dir = data_spec['dir'] || data_spec['data']
            extension = data_spec['extension'] || "html"
  
            if site.layouts.key? template
              # records is the list of records defined in _data.yml
              # for which we want to generate different pages
              records = nil
              data_spec['data'].split('.').each do |level|
                if records.nil?
                  records = site.data[level]
                else
                  records = records[level]
                end
              end
  
              # apply filtering conditions:
              # - filter requires the name of a boolean field
              # - filter_condition evals a ruby expression
              records = records.select { |r| r[data_spec['filter']] } if data_spec['filter']
              records = records.select { |record| eval(data_spec['filter_condition']) } if data_spec['filter_condition']
  
              records.each do |record|
                site.pages << DataPage.new(site, site.source, index_files_for_this_data, dir, record, name, template, extension)
              end
            else
              puts "error (datapage_gen). could not find template #{template}" if not site.layouts.key? template
            end
          end
        end
      end
    end
  
    module DataPageLinkGenerator
      include Sanitizer
  
      # use it like this: {{input | datapage_url: dir}}
      # to generate a link to a data_page.
      #
      # the filter is smart enough to generate different link styles
      # according to the data_page-dirs directive ...
      #
      # ... however, the filter is not smart enough to support different
      # extensions for filenames.
      #
      # Thus, if you use the `extension` feature of this plugin, you
      # need to generate the links by hand
      def datapage_url(input, dir)
        extension = Jekyll.configuration({})['page_gen-dirs'] ? '/' : '.html'
        "#{dir}/#{sanitize_filename(input)}#{extension}"
      end
    end
  
  end
  
  Liquid::Template.register_filter(Jekyll::DataPageLinkGenerator)
  Jekyll::Hooks.register :site, :after_init do |site, payload|
    RunMeOnce.process(site, payload)
  end